The ARRL says experimental operations on the 600-meter band have so far racked up over 200,000 hours of operation and nearly 600 contacts with zero reported complaints of interference from electric utilities, which use the band for controlling parts of their distribution networks. In addition, none of the participants in the experiment report encountering interference from utilities.
|The WD2XSH QSL card (via W4DEX.com)
The operations, using experimental license WD2XSH, have been using 465-515 kHz, in an effort to gauge interference potential once the FCC authorizes general amateur access to the 472-479 kHz (630-meter) and 135.7-137.8 kHz (2200-meter) bands. One of the matters the FCC is considering is whether hams in certain areas will need to provide advance notice of operations to nearby utility companies.
The two bands are already available to hams in a dozen countries, according to the ARRL Letter, and as of May 31 of this year, the League's experimental operators had made 578 contacts around the world. Propagation between North America and Australia has been reported as good and "relatively predictable," while paths to Japan and Europe have had less activity.